Mr Offner said it was early days, but signs were positive that the legislation would reduce alcohol related harm.

Key law changes include:

* Off-licences must close by 11pm

* On-licences must close at 4am

* Police officers will be able to issue alcohol infringement notices for a range of offences including breach of alcohol bans, lending ID to an under-18, and presenting fake ID, each incurring a $250 fine.

* Bars that serve intoxicated people or allow them on the premise risk a fine of $10,000. Police will use an alcohol assessment tool to determine whether a person is intoxicated.